The following letter riddles are taken from a book: Classic Brain Puzzlers
by Philip J. Carter and Ken A. Russell; Ward Lock Publishers,
1995 p. 68.

"These conundrums were all compiled between 1850 and 1920 and the answer
given in each case is a different letter of the alphabet, but in
no particular order. Most of these conundrums were researched by
the American word expert A. Ross Eckler for his WORD WAYS
Magazine of February 1991. Conundrums for the rare letters Q,
X, and Z are taken from Sam Loyd's 1914 CYCLOPEDIA OF
PUZZLES."